Types of Chemical Reactions
Chemical reactions are reactions which involve making and breaking of bonds between atom to yield new substances.
1. Combination Reaction:
These are the reactions in which one single product is formed from two or more reactants.
Example: i. Formation of Calcium Hydroxide.
CaO (s)(quick lime) + H2O (l) ----> Ca(OH)2 (aq)(slaked lime)
ii. Burning of Coal.
C (s) + O2 (g) ----> CO2 (g)
iii. Formation of Water.
2H2 (g) + O2 (g) ----> 2H2O (l)
2. Displacement Reaction:
These are the reactions in which highly reactive metal displaces less reactive metal from their solution.
Example: i. Fe (s) + CuSO4 (aq)(copper sulphate) ----> FeSO4 (aq)(iron sulphate) + Cu (s)
ii. Zn (s) + CuSO4 (aq)(copper sulphate) ------> ZnSO4 (aq)(zinc sulphate) + Cu (s)
iii. Pb (s) + CuCl2 (aq)(copper chloride) ------> PbCl2 (aq)(lead chloride) + Cu (s)
3. Double Displacement Reaction:
These are the reactions in which exchange of ions between reactants occur.
Example: Na2SO4 (aq)(sodium sulphate) + BaCl2 (aq)(barium chloride) -----> BaSO4 (s)(barium sulphate) + 2NaCl (aq)(sodium chloride)
4. Oxidation and Reduction Reaction:
These are the reactions in which a substance loses hydrogen or gain oxygen.
Example: 2Cu + O2 + Heat ---------> 2CuO
These are the reactions in which a substance gain hydrogen or loses oxygen.
Example: CuO + H2 + Heat -------> Cu + H2O
1.3. Redox Reaction:
These are the reactions in which one reactant gets reduced while other reactant gets oxidized. This type of reaction is also known as Oxidation-Reduction Reaction or Redox Reaction.
i. CuO + H2 + Heat ------> Cu + H2O
In above reaction-
H2 ------> H2O (oxidation)
CuO -----> Cu (reduction)
ii. ZnO + C ------> Zn + CO
iii. MnO2 + 4HCl ------> MnCl2 + 2H2O + Cl2
Observable Effect of Oxidation Reduction in Everyday Life:
Attack on metals by moisture, acids, oxygen etc., which corrode metals is called corrosion.
Example: Rusting of Iron, Black coating on Silver, Green coating on Copper.
Change in taste and smell of food material prepared by using fat or oil, because fat or oil get oxidized and become rancid.
These are the reactions in which heat is absorbed during reaction.
Example: NH4Cl (s) + H2O (l) + Heat
- -------> NH4Cl (aq)
These are the reactions in which heat is evolved during reaction.
Example: CH4 (g) + 2O2 (g) -----> CO2 (g) + 2H2O (g) + Heat
These are the reactions in which insoluble substance called precipitate is obtained when reaction completes, is known as precipitation reaction.
Example: Na2SO4 (aq) + BaCl2 (aq) ----> BaSO4 (s) + 2NaCl (aq)
1. Chemical Reaction, 2H₂O → 2H₂ + O₂ is a-Synthesis Reaction
Single Displacement Reaction
Double Displacement Reaction